Prostheses can be useful to enhance the life experience of users, such as for those who lose or are born without a portion of a limb. As the operability of such prostheses improves, so does the experience of the user. Accordingly, prosthetics have continued to develop over the years to provide enhanced capabilities.
As features are added to prostheses, their complexity also tends to increase. For instance, where mechanical control and actuation are implemented, related componentry can tend to be bulky and require significant power. Other issues with prostheses relate to the challenges that users face in using them. For instance, balance is a major challenge for persons with lower limb amputation, with about 52% experiencing a fall annually and with fear of falls being a significant factor in limiting activity. Walking in settings with lateral balance perturbations, such as on uneven terrain or across side-slopes, can be especially problematic. Many lower-limb prostheses have limited motion in ankle inversion/eversion (IE), and even those with significant IE range of motion support this motion through substantial ankle stiffness. Thus perturbations under the foot create an ankle moment, which can in turn perturb lateral balance. Because gait is naturally less stable in the lateral direction, these perturbations have increased impact on the lateral balance ability of persons with lower limb amputation.
These and other matters have presented challenges to the use of prostheses, for a variety of applications